1. Field of the Invention
The present invention relates generally to the cleanup of vessels containing radioactive waste, and more particularly to an impeller device with a folding blade assembly that can be inserted into a small entrance in the vessel and rotated to mix the radioactive waste into a pumpable slurry, which can then be pumped out of the vessel.
2. Description of the Prior Art
There are a large number of vessels of various sizes and shapes buried underground throughout the United States, which contain radioactive waste. Many of these vessels are leaking and must be cleaned out, and the waste disposed of properly. In many cases, the waste is not a pure liquid, but contains dirt, sand, crystallized salts and various other solid particles. These particles are also a hazard. In order to clean these vessels, the waste must be mobilized into a liquid or slurry that can be pumped out of the vessel. One way to mobilize these materials is by agitating the liquid and solid mixture with a mechanical mixer.
The difficulty with this process is that most of these vessels are not readily accessible with any standard type of mixer. Most of these vessels usually have very small ports on the top surface of the vessel; therefore, a normal size mixer impeller will not fit through these ports, and it is too dangerous to attempt to assemble an impeller through the port itself. Additionally, the agitator should also be removable from the vessel after mobilization and after the cleansing process has been completed, so that the tank can be removed from the ground, filled with concrete or made safe by other means.